Printed circuitry



Nov. 3, 1959 N. B. WALES, JR 2,911,605

PRINTED CIRCUITRY 2 Sheets-Sheet 1 Filed Oct. 2, 1956 INVENTOR Mmzmsz Lt Muzak BY MW 29 ATTORNEY Nov. 3, 1959 N. B. WALES, JR

PRINTED CIRCUITRY 2 Sheets-Sheet 2 Filed Oct. 2, 1956 INVENTOR Mm'A/wn a M4155; lg

Fhll-a-MM ATTORNEY 2,911,605 I I PRINTED CIRCUITRY Nathaniel n'wales, In, New York, N.Y., assignor to e the material of which Strip 2 is made Monroe Calculating Machine Company, Orange, NJ., a corporation of Delaware Application October 2, 1956,, Serial No. 613,582 2 14 Claims. Cl. 336-200) This invention pertains to printed circuit structures and deals with a novel concept in printed circuit structures a pared with prior art devices.

It is a further object of'the invention to achieve such a reduction in volume in such a manner as to make the most efficient usage of the impedance volume in con-' tributing to the impedance effect of the device.

It is a further object of the invention to provide such a device which fulfills the-above stated objects and which readily lends itself to mass production manufacturing techniques employing automatic machinery.

As set forth iii-detail subsequently, the above objects are attained by providinga structure in the form of a plicatedor fan-folded strip of electrically insulating sheet material on which is provided a printed circuit pattern defining adesired electric circuitarrangement in laminar or stacked form. e

A feature ofthe invention resides in novel printed circuit arrangements forestablishing localized electrical connection between two circuit portions separated by interposed insulating means. I

This invention represents an improvement over devices of the'nature of, those disclosed in United States Patent 1,647,474 granted November 1, ,;1927 to F. W. Seymour. I i

For the purposes of the present disclosure, the inven- 2,911,505 Patented Nov. 3, i959 ice 2 1 and 2 a compact impedance 1 comprising a continuous sheet strip 2 of.thin,.pliab1e, electrically insulating back ing material arranged in plicated (fan-folded) manner so as to provide a plurality of separate overlying layers numbered 3-13 inclusive. Mylar (polymeric ethylene terephthalate) has been found to be eminently well-suited as Provided on and bonded to some of the layers is. a

thin coating of electrically conductive material .15, for

example'silver or. aluminum, arranged-in such a pattern as to form a coil. One of these coils L3 is shown in Fig.

'1 provided onithe-outer surface of layer 3, and immediately underlying a transparent gummed tape member 17 which is wrapped around fan-folded strip 2 to maintain said strip in folded disposition.

. As will be described subsequently in greater detail, certain spaced pairs of layers are each provided with serially connected coils, whilethe layer intermediate said pairs of layers is employed to establish electrical connection between the two coils lying on each side of said interoutermost turn of coil L3, over the common fold line at ,which layers-3 and 4 are interconnected, and to the outermost turn of coil L4.

Adjacent layers 6-and 7 are likewise provided with coils L6 and L7 on their upper and lower surfaces respectively.

4 Coils L6 and L7 are serially connected electrically by a line 19 of said conductive material 15 extending between said coils and over the common fold line between layers 6 and 7.

Layer 5 intermediatelayers 4 and 6 is not provided with a coil but israther employed to' establish electrical connection between coils L4 and L6 disposed on either side thereof as follows. As shown in Fig. 5, a tab 25 integral with layer 5 is folded back on the under surface of said layer. Tab 25 is-provided with an electrically conductive coating 26 which extends continuously from the tab proper over the hinge line 27 of the tab and back along the upper surface oflayer 5 so as to underlie the innermost turn of coilL4. It' will be noted that the tab portion of coating 26 is of sufficient extent to overlie the innermost turn of coil L6. Accordingly, when the Variship as in Figs. 1 and 2, the coating 26 will contact the innermost portions of coils L4 and L6 and thereby serve tion is shown and described as embodiedin an inductmice. It will be understood, however, that the broader aspects of theinvention and certain of its features can ing the fan-folded blank just prior to bringing the various plications into their final intimate relation of Figs.-'1 and 2.. a

Fig. 6 is atopplan View of a modified blank arrangement.

Fig. 7 is a view similar to Fig. 5 showing the manner of fan-folding the blank of Fig. 6. I I Referring now to the drawings, there'is shown in Figs.

to establish a serial electric connection between said coils, which are otherwise insulated from eachother by layer 5.,

A similar tab 29, integral with layer 8 and having an electrically conductive coating 30, establishes serial electrical connection between coils L7 of layer 7 and L9 of layer 9 in like fashion. i

Fig. 3 illustrates a blank from which the afore-described impedance can economically be made. "Said blank comprises an elongated strip 2 of the previously mentioned sheet material such as Mylar of one or onehalf mil thickness.

Strip 2 may be considered as being subdivided along. its length into a plurality of zones or portions 3, 4, 5, etc.,

corresponding to the previously described layers. Strip the various zones into consecutive stacked or laminar contactmgrelationshlp.

Appliedan'd bonded to the various zones in the sequence set forth below isan arrangement of the electrically conductive material 15 forming the various coils and connector elements described previously.

, 3 Thus, zones 3 and 4 (Fig. 3) are each provided on their front faces with a coating of the electrically conductive material 15 defining respective clockwise spiral coils L3, L4 and their connecting lead 18. Zones 6 and 7 are providedfon their reverse faces withan electrically conductive coating defining coils. L6, L7Eand their connecting lead 19. As viewed in Fig. 3, coils L6 and L7 are counterclockwise spiral configuration, andare shown in broken lines since they are disposed on the rear faces of their respective zones 6 and 7.

The central portion of zone is slit toform tab 25 adapted to be folded back along hinge line 27. Applied to zone 5 is conductive coating 26 applied to the forward face of tab 25 and extending overlhinge line 27 tothe portion of zone 5 outside tab 25.-. i

Zones 9 and 10 are provided with a coating of electrically conductive material arranged in a pattern which is substantially identical with that applied to zones 3 and 4. I

Zone 8 is centrally slit in the manner of zone 5 t form tab 29 adapted to be folded'upwardly along hinge line 3 1. Conductive coating 30 applied to the rear face of zone 5 extends across said hinge line 31.

The above-described pattern sequence as applied to the six zones numbered 3 through 8 inclusive, constitutes the basic repeating sequence applied to strip 2. This basic repeating sequence consists of: two serially connected clockwise spiral coils L3 and L4 provided on one Thereupon, the various folds or layers are brought into closely adjacent, intimate relationship (as in Fig. 2), and

and are sodisposed that their respective flux fields are surface of the strip; tab 25 and its associated conductive coating 26 applied to the same side as said coils; two serially connected counterclockwise spiral coils L6 and L7 on the obverse face of the strip; and tab 29 and its associated conductive coating 30 also on the reverse strip face.

The above-described coil and connector six-zone sequence is repeated beginning with zones 9and 10. Coils L9 and L10 thus represent the first two elements of the repeated sequence. Zone 11, a portion of which is shown in Fig. 3, will therefore be a duplicate of zone 5. Similarly, the next three consecutive zones (not shown) will respectively be duplicates of zones 6-8 inclusive. In such fashion, the basic arrangement of the first six zones (-38) will be repeatedly carried out along strip 2 for as great a length as desired.

The electrically conductive material 15 can be applied to backing strip 2 by any of the well-known printed circuit manufacturing techniques, as, for example, galvanic disposition, printing, stencilling, etching, fashioning metal foil to the appropriate shape and securing it to the nonconducting backing strip, etc.

The inner end of each of the various coils issorne- What widened as shown at 33 and 33a in Fig. 3 to provide an augmented contact area for establishing electrical con nection to and from the coils. I

Further, each of the coil zones, 3, 4, 6, 7, 9, 10 etc. is provided with a central hole 34, while the zones 5, 8 will of course contain central apertures 25a, 29a after respective tabs 25 and 29 are folded back. When strip 2 is folded to bring the variouszones into layered or laminar disposition as in Figs. 1,' 2, and'5, the various holes and apertures will be substantially axially aligned to form a single central tubular bore 35 .(Figs. 1, 2). This central bore 35 is adapted to receive a ferromagnetic core for use, if desired, in conjunction withthe fanfolded coil structure. While holes 34, 25a, .and 29a have been shown as arcuate in the drawing, they may be square if desired. 1 i a r The 'abovedescribed blank of Fig. 3 is adapted to be additive with regard to one another. It should be noted that Mylar strip 2 is magnetically permeable and will therefore not inhibit the formation of the flux field.-

Thus, coils L3 and L4 are disposed on the remote outer faces of the adjoining pair of layers 3 and 4, the coils thereby being insulated from one another by the insulating material of strip 2. Lead 18, extending over the common fold line between layers or plications 3, 4, serially interconnects the outer turns of coils L3 and L4.

In like fashion, coils L6 and L7 are provided on the remote outer faces of adjoining layers 6 and'7 and are serially connected by lead 19.

The intermediate plicated portion or layer 5 serves to separate layer 4 from layer 6, thereby providing insulating means between coils L4 and L6. The desired localized serial connection between said coils L4 and L6 is achieved by conductive coating 26 carried in part by tab 25 and extending through aperture 25a over the edge of said aperture.

Layer 8 similarly functions as a separating insulating means between layers 7 and 9, serial connection being established between coils L7 and L9 by conductive coating '30 carried partly by tab 29 and extending through aperture 29a over the. edge of said aperture.

To maintain the layers of the plicated article so formed in the intimate compressed relationship of Figi-Z, strip I 17 of adhesive-coated insulating tape is wrapped around the fan-folded strip, adhesiveside in, with the ends of said tape overlapped as shown in Fig. 2. The tape 17, in addition to maintaining the fan-folded strip 2 in compressed condition also serves to insulate any exposed conductive portions of the stack from undesired contact with any. electrical conductor which may be adjacent thereto in the environment in which the article of the invention is to be used. Tape 17, which may be of the same Mylar material as strip 2, further functions to hold lead-in wires 40 and 41 securely in place.

While tape 17 has been shown in Fig. l of the drawing as transparent for clarity of disclosure, itgwill be recognized that said tape may be made opaque or translucent, if desired. 1 V V p I Figs. 6 and] illustrate a modification of the invention in which the electrically conductive material 15 providing the electriccircuitry of the device need be applied to only zones 51', 52 with substantially identical clockwisespiral trical connection between coil 54. and coating,65, while printed circuit coils 53, 54 connected by conductive lead 55. Zones 56 and 57 are each centrally slit to provide respective tab members 60 "and 61, adapted Ito bej' folded under along the respective hinge lines 62, 63. Electrically conductive coatings 64, extend from eachtab over the respective hinge lines 62, 63 to the portions of said zones 56, 57 on the opposite sides of saidhinge lines.

Zones 66 and 67 are provided with clockwise'spiral coils 68, 69 connected by lead 70.

' Fig. 7 illustrates the manner inwhich the blanket Fig. 6 is fan-folded after tabs 60 and 61 have beenfolded rearwardly along their respective hinge lines 62, 63'. It will be seen that conductive coating 64 establishes elec-' coating 65 establishes connection between coating 64 and coil 68. J i

lishing electrical connection between coils.

The modified form shown in Figs." 6 and 7. will thereafter be provided with lead-inwires and an exterior binding tape wrapping, corresponding respectively to elements 40, 41 and 17 of the species of Figs. 1-5. i

As stated previously, the device of Figs. 6 and 7 presents the advantage of providing all the necessary printed circuitry on only one side of the Mylar backing strip. v

However, the Figs. 6 and 7 modification does not make as efficient use of the strip, since each alternate pair of adjacent zones is employed as a linking means for estabe 50% of the strip length comprises coilzones.

This is in contradistinction to the more efiicient arrangement of Figs. l5, whereinonly each third zone is used Thus, only as a connector means between coils lyingon each side of that zone. In the form of Figs. 1-5, therefore, 66 /s% of the strip length comprises coil zones contributing to the overallmagnetic field produced.

I claim:

. 1. An electric circuit structure comprising a plicated strip of thin, flexible, sheet-like electrically insulating material, individual printed circuit coil means provided only on each plication of separated pairs of adjoining plications, said pairs being separated by an intervening plicated portion of said strip, .the two coil means of each of said pairs being disposed on the respective remote outer faces of said adjoining plications, the adjacent confronting inner plication of separated pairs tervening portion, said intervening .portion including a folded-back tab carrying a portion of said conductive material on one side of said intervening portion and further including an aperture through which said con ductive material passes extends to the other side of said intervening portion.

9. An electric circuit structure comprising first electrioal conductor means, second electrical conductor means, means interposed between and insulating said first and second conductor means from each other, said interposed insulating means being provided with an aperture and faces of said adjoining plications presenting only the insulating'material of said strip to each other.

2. The invention set forth in claim 1, and further comprising means serially electrically connecting all said coil means. f I

3. The invention set forth in claim 2, said last named means including a printed circuit portion on said remote outer faces and extending over the common fold portion between said adjoining plications, said printed circuit portion serially connecting said two coil means at their ,outer portions.

4. Thte invention set forth in claim 2, said connecting means including conductive means provided on said intervening plicated portion of said strip, said conductive means serially connecting the coil means lying on opposite sides of said intervening plicated portion of said strip.

5. The invention set forth in claim 2, said intervening plicated portion being provided with an aperture and a folded-back tab adjacent thereto, saidconnecting means including a thin layer. of conductive material on said intervening plicated portion, said conductive material extending through said aperture and being carried in part by said tab, said conductive material contacting the coil means lying on opposite sides of said intervening plicated portion.

6. In an electric circuit structure, a thin flexible sheet of electrically insulating material, a tab struck from said sheet and folded out ofthe plane of said sheet to one side thereof, thereby providing an'aperture in said sheet, a thin layer of conductive material provided on the opposite side of said sheet and extending through said aperture over the fold line of said tab onto the outer face of said tab. v j I 7. An elcctricfcircuit structure comprising a plicated strip of thin, flexible, sheet-like electrically insulating material, printed circuitimpedance means provided only on each plication of separated pairs of adjoining plications, said pairs being separated by an intervening plicated portion of said strip, the impedance means of each of said pairs being disposed only on the respective remotewouter faces of said adjoining plications, the adjacent confronting inner faces of said adjoining plications presenting only the insulating materialof said strip to each other.

8. An electric circuit structure comprising a plicated strip of thin, flexible, sheet-like electrically insulating material, individual printed circuit coils provided on each folded-back tab means, means for establishing localized electrical connection between said first and second conductor means, said connection means comprising a thin layer of conductive material provided onsaid interposed insulating means, said conductive material extending through said aperture and being carried at least in part by said tab means, said conductive material contacting a portion of said first and second conductor means.

10. The invention set forth in claim 9, said interposed insulating means comprising a thin pliable sheet, said tab means being integral with said sheet.

11. An electric circuit structure comprising first electrical conductor means, second electrical conductor 1 means, means interposed between and insulating said first and second conductor means from each other, said interposed insulating means including an aperture and a tab adjacent to said aperture, said tab being folded back along a face of said insulating means, means for establishing localized electrical connection between said first and second conductor means, said last connection comprising a thin continuous layer of conductive material provided on the opposite face of said insulating means and the outer face of said tab and extending through said aperture over an edge thereof, said layer of conductive material contacting a portion of said respective first and second electrical conductor means.

12. An electric circuit structure comprising first electrical conductor means, second electrical conductor ductor means from each other, a tab struck from and folded back along a face of said insulating member, thereby providing an aperture in said insulating member adjacent said tab, a layer of electricallyconductive material provided on the opposite face of said member and extending over an edge portion of said aperture onto the outer face of said tab, the portion of said coating on said opposite face contacting one of said conductor means, and the portion of the coating on the outer face of said tab contacting the other conductor means, whereby electrical connection is established between said first and second conductor means.

13. In an electric circuit structure, a .thin flexible sheet of electrically insulating material, a tab secured to said sheet and folded out of the plane thereof, a thin layer of conductive material provided on said sheet adjacent said tab and extending onto a face of said tab, an elec; tricalconductor means lying out of the plane of the sheet, said folded tab contacting said conductor means, the conductive material provided on the tab engaging said conductor means and thereby establishing electrical comof adjoining plications, said pairs being separated by an intervening plicated. portion- 7 2,911,605 7 8 munication between the conductive material carried by a FOREIGN PATENTS the sheet and the conductor means.

' 14. The invention according to claim 13, said tab being 16 Ailistlaliai Q g- 3, 1955 snbstantlally narrower than said sheet. OTHER E RENCES References Clted m the file of thls patent fFoldable Printed Circuits, Electronic Equipment, UNITED STATES PATENTS pages 15 17 August 1955 7, 1,647,474 Seymour Nov. 1, 1927 Etched Circuits, Wireless World, page 488, Decem- 2,014,524 'Franz Sept. 17, 1935 0 er 9 I UNITED STATES PATENT OFFICE CERTIFICATE 0E CORRECTION Patent Nov 2,911,605 November 3 1959 Nathaniel B. Wales, Jra

Patent should read as corrected below.

Column 2 line 24, after "line" for the indistinot numeral read 18 column 3, line 55, after "zones" .etrike out the comma; column 4, line 42', after ocmdition" insert a comma; column 5, line 40, for "Thte read me The column 6, line 17, after "material" ,stfike out "passes"; column 6, line 43, for "said; last cormeotion" read ,seici connection means Signed; and sealed this lUth day of May 1966 (SEAL) Attest:

KARL Ho Mill-NE ROBERT C. WATSON Attesting Officer Commissioner of Patents UNTTED STATES PATENT oEETcE CERTIFICATE :I CORRECTTON Patent Nos. 2,911,605 I November 3, 1959 Nathaniel Ba Wales, Jra

It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 24, after "line for the indistinat numeral read 18 column 3,. line 55, after "zones" strike out the semi column 4, line 42', after "condition" insert a comma; column 5, line 40, for "Thte'" read w The column 6, line? 17,. after "material strike out "passes"; column 6, line 43, for "said last connection" read said connection means Signed and sealed this 10th day of May 1960,

(SEAL) Attest:

KARL MINE ROBERT c. WATSON Attesting ()fficer Commissioner of Patents 

